The science of smaller than small particles.

Nanotechnology utilises extremely small dimensions of elements. We call it the ‘nanoscale’. One nanometer is a billionth part of a meter. Or you can say, 10,00,000th part of a millimeter. A minute size that opens up a big world of possibilities across contemporary chemistry, biology, material sciences, and engineering.

Thanks to nanotechnology, we now have the ability to see and control individual atoms and molecules. Materials formed by using the principles of nanotechnology -- whose properties lie between those of macroscopic solids and atomic systems -- are known as nanomaterials. They display unique optical, magnetic, electrical, and other physico-functional properties. These phenomena are redefining our electronics, medicine, and other fields.

Nanoscience and nanotechnology involve the ability to see and control individual atoms and molecules. Nanomaterials are of interest because at this minute a scale, they display unique optical, magnetic, electrical, and other physico-functional properties. These phenomena have a great potential for applications in electronics, medicine, and other fields.

It was observed that the quantum properties of matter can differ at the nanoscale. For e.g., a material behaving as an insulator at the molecular level can express the properties of a conductor when looked at its nanoscale level. Such discoveries have opened up a worldwide quest to explore. The transformation that nanotechnology can bring to all contemporary sciences is an exciting prospect.

Fact

Although nanotechnology may seem like a new-age realm, nanoscale materials have been in use for centuries. Alternate-sized gold and silver particles created colours in the stained-glass windows of medieval churches, hundreds of years ago. The artists back then were unaware that they were changing the composition of the materials they were working with while creating those masterpieces.

What are Nanomaterials?

The nanoscale is at the one billionth part of a meter. Particles whose external dimensions or internal structure dimension or surface structure dimension lies in the range of 1nm to 100nm are considered as Nanomaterials. They are invisible to the naked eye but can be observed with the help of a Scanning Tunnelling Microscope (STM) or the Atomic Force Microscope (AFM).

At this scale, these materials have unique optical, electronic, mechanical and quantum properties vis-à-vis their molecular scale behaviour.

Nanomaterials can be of natural existence, artificially manufactured, or incidentally formed. With the advances in the research, nanomaterials are being commercialized and used as commodities.

Properties of Nanomaterials

Largely, nanomaterials display three key properties – mechanical, electrical and optical.

A drastic change in the properties of nanomaterials can be observed when they breakdown to the nanoscale level. As we go towards the nanoscale level from the molecular level, the electronic properties of materials get modified due to the quantum size effect. Change in the mechanical, thermal and catalytic properties of the materials can be seen with the increase in surface area to volume ratio at the nanoscale level.

Many of the insulator materials start behaving as conductors at their nanoscale dimensions. Similarly, as we reach the nanoscale dimensions many interesting quantum and surface phenomena can be observed. Particle size, shape, chemical composition, crystal structure, physico-chemical stability, surface area, and surface energy, etc… attribute to the physico-chemical properties of the nanomaterials. As the surface area to volume ratio of the nanomaterials increases, their surface becomes more reactive on itself and other systems.

The size of the nanomaterials plays a significant role in their pharmacological behaviour. When nanomaterials interact with water or other dispersion media, they can rearrange their crystal structure. The size, composition, and surface charge of the nanomaterials affect their aggregation states. The magnetic, physico-chemical and psychokinetic properties of these materials get affected by surface coating. These materials produce ROS (Reactive Oxygen Species) when their surface reacts with oxygen, ozone, and transition materials.

At the nanoscale level, the interaction between particles is either due to the van der Waal forces or strong polar or covalent bonds. The surface properties of the nanomaterials and their interactions with other elements and environments can be modified with the use of polyelectrolytes

Nano Material in Nature

Nanomaterials can be found as either engineered nanomaterials, incidental, or of natural existence. Engineered nanomaterials are manufactured by humans with some desired properties. They include carbon black and titanium dioxide nanomaterials. Nanoparticles are also produced due to mechanical or industrial processes incidentally – e.g., in vehicle exhausts, welding fumes, cooking, and fuel heating. Incidentally produced atmospheric nanomaterials are also known as ‘ultrafine particles’. Fullerenes are the nanomaterials produced due to the burning of biomass, candles, etc.

Naturally existing nanomaterials are formed by phenomena such as forest fires, volcanic ash, ocean spray, weathering of metals, etc. Some of the examples of nanomaterials present in biological systems are the structure of wax crystals covering lotus plants, structure of viruses, spider-mite silk, blue hue of tarantula spiders, and butterfly wing scales.

Particles like milk, blood, horn, teeth, skin, paper, corals, beaks, feathers, bone matrix, cotton, nail, etc., are naturally occurring organic nanomaterials.

Clays are the example of naturally occurring inorganic nanomaterial as they are formed due to crystal growths in diverse chemical conditions on the earth’s crust.

Nanoscience and technology in our daily life
Advantages & Applications of Nanomaterials

Today, nanomaterials are being highly commercialized. Some of the commercial nanomaterials available in the market are cosmetics,
stain-resistant & anti-microbial textiles, electronics, sunscreens, paints, etc.

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